Drug delivery devices and applicators for dispensing known quantities of therapeutic agents to animals are well known in the art. While there are numerous ways to deliver these therapeutic agents to the coats and skins of the animals, many of these methods are either ineffective and/or present safety risks to the animal or user during or after the dispensing activity. More particularly, because a physical connection must be achieved between the applicator tip and the drug delivery device during the dispensing activity, there is inherently a risk that the connection will be inadequate, thereby permitting some of the therapeutic agent to leak out of the device and into physical contact with the user. Not only is this leakage wasteful and messy, it also places the user at a heightened risk of suffering from a skin irritation or other such health concern, particularly if the user comes into direct contact with the agent. These health and safety risks can be of particular concern when a controlled substance is used as the dispensing agent.
In addition to leakage concerns, many conventional drug delivery devices also have a tendency to leave some residual therapeutic agent inside the body of the device after dispensing is completed. This is not only wasteful both in terms of product and cost, but also presents an increased safety risk to any individual who may contact the device after it has been used. More particularly, if the device still contains a poisonous or skin irritating ingredient, a person may suffer a serious health risk (or even death) if they handle the component after it has been discarded. Further, a residual amount of a controlled substance remaining in the dispenser after dispensing may create an issue of unauthorized use of a controlled substance.